The present invention generally relates to a combustion chamber of the type including a fluidized bed. In particular, the present invention is directed to an assembly for initially heating the fluidized bed through the use of a hot gas flowing in heat exchanger tubes extending through the fluidized bed.
It is well known that a fluidized bed material must be heated to a temperature in the vicinity of the fuel ignition temperature before ignition can be accomplished. A known fluidized bed combustion chamber employs a separate heating device for supplying a heated gas, usually air, into the combustion chamber in the same direction in which the combustion air is supplied. This known combustion chamber has proven less than satisfactory in requiring the special heating device which serves a limited function while considerably increasing the operating cost.
As will be discussed in detail hereafter, applicant's new and useful invention solves the problem facing known fluidized bed combustion chambers with a combustion chamber including a simple and inexpensive assembly for supplying superheated steam capable of sufficiently heating the bed material to allow for ignition.